Move Lit examples into their own lit/ directory

[ava-cassiopeia]

An attempt at organizing the code a bit to distinguish shared web code from framework-specific web code. This is some of the steps toward the final repo structure, hopefully putting us in a good position to update to the final structure once we finalize it.

tests/ is top level in web/ right now, which will probably eventually be folded into lib/, since it only seems to test lib/ anyway.

This is setup for future work in which I'll try to extract shared code from the Angular and Lit code into a shared library.

Reviewer hint: The key code to review is the package.json files, which is where I made some small tweaks to refs with the move.

[jacobsimionato]

Hey can we aim for a structure something like what is proposed here:
https://docs.google.com/document/d/1y6JLGp-1CTKQfT7CdnSVVjPN3qhl9-Ga3V3JpHQHNR0/edit?tab=t.0#bookmark=id.99vgialtqq1l

E.g.

• Seeing as web/src/0.8 depends on lit, it's all a lit renderer, right? So lets put it in a "lit" folder.
• Let's standardize and have all example code in "samples" folders so it's clear the difference between samples and actual library code
• Ideally, let's group renderers together in a "renderers" folder, so that the difference between agent libraries and renderer libraries is clear.

[ava-cassiopeia]

Seeing as web/src/0.8 depends on lit, it's all a lit renderer, right? So lets put it in a "lit" folder.

web/lib is a bit of a tangle, as it is also imported by Angular code. There's probably some stuff that is lit-specific though, so that needs to be untangled (I'll do that in a followup PR to keep this PR somewhat comprehensible).

Let's standardize and have all example code in "samples" folders so it's clear the difference between samples and actual library code

Done, modulo inspector, because I don't really know where to put that (should it be under tools/ somewhere..?)

Ideally, let's group renderers together in a "renderers" folder, so that the difference between agent libraries and renderer libraries is clear.

Sounds good - that's another I'll do in a followup to simplify this PR.

[ava-cassiopeia]

I'm going to move ahead with this PR so that it doesn't end up becoming a merge conflict nightmare, but I'm happy to follow up on any further organization steps once we finalize the doc.

Will address further file structure changes in future PRs